


The Stallion

by thewinchesterlifestyle



Category: Supernatural
Genre: Angel Wings, Bestiality, Bottom Castiel (Supernatural), Boypussy, Breeding, Come Inflation, Dubious Consent, Gags, Interrupted Ritual, Loss of Virginity, M/M, Magic, Marathon Sex, Mating Cycles/In Heat, Other, Outdoor Sex, Restraints, Sex Magic, Size Difference, Size Kink, Unicorns, Virgin Castiel (Supernatural), Witches, angelic heats, cross-species breeding, hole gaping, magic makes ALL THINGS possible, unnatural recovery time
Language: English
Status: Completed
Published: 2019-05-24
Updated: 2019-05-24
Packaged: 2020-03-13 21:32:01
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,321
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18949045
Author URL: https://archiveofourown.org/users/thewinchesterlifestyle/pseuds/thewinchesterlifestyle
Summary: Unicorns, soft and sweet mares, hadalwaysapproached Castiel. The magical creatures were drawn to the pure and untouched scent virgins carried and Castiel being an angel was no exception.Castiel had never imagined his untouched scent would attract a stallion.





	The Stallion

**Author's Note:**

> This has been basically sitting on my laptop for a couple months, since I received it, and I apologize for the wait between posting new things.
> 
> Hopefully this is something a few of you might enjoy. To the prompter...I hope this is at least close to what you were thinking. I'm blaming a half realized idea for fleshing out your prompt the way I did.
> 
> Written for a prompt.

Castiel struggled with the bindings keeping him strapped down, the sigils flaring and subduing him with each movement, as his heat sunk its teeth into him and a need he wanted desperately to ignore started to make itself known. They had left him in the middle of a clearing, fires lit all around, as the witch who had managed to capture him went to collect the coven that planned to use him for a ritual.

A ritual requiring a virgin and sex magic.

Each member would penetrate him, come in his cunt and the coven leader would slit his throat with the ceremonial dagger etched with angelic sigils as he was fucked until death came for him.

The sigils flared and his strength was reduced, again, as a low, trembling whine escaped into the still night. He could feel the way his wings, spread out in an offering no one was taking, shuddered as the scent of his heat and his wing oil filled the clearing.

He would give anything, _anything_ , for relief.

Castiel shouldn’t be going into heat, not without a viable angel to mate him around, but luck was never on his side and the only ones coming were witches. He squirmed as cool wind brushed his naked body. A choked whimper escaped  at the feeling of it brushing where he was wet and loose and _empty_.

The witch had left him spread wide, holes exposed and waiting, with a gag shoved into his mouth. His inner muscles clenched, needing something to grip, when the sound of _something_ large approaching had him tensing.

He was torn between desperate relief that at least if the witches were back he would be _full_ and a muted kind of horror at the vulnerable position he was in. They were more than equipped to complete their ritual and there was precious little he could do since he’d gone off on his own with the Winchesters or any kind of ‘backup’.

A handsome pure white unicorn stepped into the clearing, snorting and stamping the ground with his hoof, as Castiel sagged where he was strapped down. Unicorns always found him, whenever they were near, and their presence had always been soothing. The creatures had a calming effect on virgins and untouched angels were no exception.

Castiel felt his muscles relaxing and the anxiety, the stress and horror, he’d been feeling start to ease as the unicorn moved closer. Idly, mind slowly slipping into a calm heat frenzy instead of the violently desperate one typically associated with angelic heats, he wondered if there were others in the area. It was rare to see one by themselves. The sound of hooves came closer and closer until the magnificent creature was moving around him.

His brow furrowed. Typically they would nuzzle against him, his face or hands, before either allowing him to pet them or wandering off.

It wasn’t until the unicorn was behind him, rearing up and landing on him that Castiel realized it was a stallion. His scent had drawn a stallion to him for the first time and as the creature thrust against him, snorting and grunting, he groaned lowly at the feeling of being mounted.

A massive, monstrous cock missed and missed his soaked entrance until it didn’t. The stallion sheathed himself inside Castiel’s dripping wet cunt with one powerful, hard thrust that had Castiel wailing into the gag filling his mouth.

The stallion fucked him, hard and deep thrusts, as Castiel’s bound body moved with each thrust of the stallion’s hips. It wasn’t like a regular horse, a relatively quick event. Unicorns were a magical creature—powerful, strong and with supernatural stamina that would see them through an entire breeding session until success was achieved.

He could feel the way his body had adjusted, angels made to be bred were created so that they could adjust to fit the size of their mating partner, as the unicorn hammered into him with a kind of rapidness he had not known was possible.

Unicorns, it seemed, could not only run fast but they fucked at an unnaturally fast pace as well.

Slowly, effortlessly, his instincts had him going completely limp in submission as his wings lowered in acceptance at the domination of a worthy mating partner. The soft sound of oil dripping on the grass was covered up by the sounds of the unicorn’s gigantic cock plowing through the copious amounts of slick his body was producing to ease the way.

It was a long mounting, the unicorn periodically emptying a load into his fertile womb and pausing briefly before mounting once more and resuming the punishing pace.

A stallion, a unicorn stallion, was driven to mount and breed until the mare underneath them was swollen with their potent seed and their attempts had resulted in a successful breeding. The unicorn’s magic would sustain its body until the task was finished and a new life had been created.

Castiel tried to push back into each thrust, body yearning to be able to move, but the witch had thoroughly secured him and the only thing he could do was lie there and take the stallion’s massive cock in his greedy cunt.

Muffled moans and whimpers and hitched whines competed with the sounds of fucking and breeding.

He could see, through pleasure and heat desperate eyes, the sight of several other unicorns just outside of the clearing where the moon’s light brushed against the proof they were carrying foals in their swollen bellies. Castiel’s inner muscles clenched repeatedly, squeezing the stallion’s thick cock, as he came with a wail and his cunt was flooded with his release.

Distantly he heard a shriek of outrage as the witch came back to discover a unicorn had stolen his virginity and was in the process of actively breeding him but Castiel didn’t care. His mind and body were drowning in desperate pleasure as he strained to push back into the stallion’s thrusts to, somehow, take the creature deeper.

The unicorn slammed deep, hips jerking against Castiel’s round ass, as the soft underside of the unicorn’s belly rested heavily on his back as the stallion came inside of him again.

It was days.

Days and days of the stallion mounting him, fucking his cunt and filling his womb to the point that Castiel was in agony that only lessened when the stallion briefly left him and he was empty allowing the stallion’s come to escape his gaping entrance. The pain of being too full didn’t stop the need to be fucked and bred. Castiel _wanted_ the stallion to mount him, he _needed_ the creature to keep climbing up and fucking back into his thoroughly ruined cunt.

He could feel the creature’s magic, the intrinsic magic that only a unicorn possessed, wrapped around him constantly as it sunk into his grace, his vessel and his womb until the stallion mounted him for the last time on the sixth day.

The stallion didn’t pull out after coming inside of him like it typically did—instead it maintained its position as it started fucking into him once more. After hours of continuous fucking and breeding and sobbing at the feeling of too much the unicorn thrust deep into him for the last time.

It paused, grunting, as Castiel was crushed to the stand before it shifted and slipped out of him with a wet, filthy squelching sound.

Castiel whined lowly as the other unicorns came into the clearing, surrounding him. The stallion moved away from him with a pleased air if Castiel had to put a name to it. He didn’t need to access his grace to know _why_ the stallion had stopped—he could feel the change as all angels designed to be bred could feel it.

His grace and the stallion’s intrinsic magic had formed a bond allowing the stallion to father the foal Castiel could feel nestled in his womb.

**Author's Note:**

> I don't think I've written anything with a unicorn mounting one of the SPN characters so this was new. I also took some liberties and made up my own rules for unicorns/stallions breeding because.
> 
> So Cas went from being a virgin sacrifice, strapped down for a gangbang and a ritual death, to spending days being mounted by a very enthusiastic unicorn stallion and being bred with a sweet little foal. I'll leave you to wonder _why_ the witches just left him there underneath the unicorn instead of making an attempt to use him for a different ritual.
> 
> Please remember to leave a comment and let me know what you thought. Comments are, honestly, great motivators when it comes to me posting up more fics for you all to enjoy!
> 
>  
> 
> If you have a bottom!Cas prompt you can send it [here](https://surveynuts.com/surveys/take?id=176805&c=5013482597THNN). I'm looking for a few fresh prompts. If you want to go crazy with something taboo, something dark or unusual don't be shy (you all don't have to apologize for the craziness when you prompt!).


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